Portable picture transmission apparatus



H CARLSON March 7, 1939.

PORTABLE PICTURE TRANSMISSION APPARATUS Filed June 4 4 Sheets-Sheet l INVENTOR flame, 3 11 11 L- ii i t U LEQ i t r F LWt Ur ATTORNEY March 7, 1939. H. CARLSON 2,149,277

PORTABLE PICTURE TRANSMISSION APPARATUS Filed June 4, 1936 4 Sheets-Sheet 2 FIGZ INVENTOR B w. (MW g ATTORNEY March 7, 1939. H. CARLSON PORTABLE PICTURE TRANSMISSION APPARATUS Filed June 4, 1936 4 Sheets-Sheet FIG.4

INVENTOR 5 mg Mm FIG. 5

Y ng wtfiw ATTORNEY March 7, 1939. H. CARLSON.

PORTABLE PICTURE TRANSMISSION APPARATUS Filed June 4, 1936 4 Sheets-Sheet 4 FIG. 9

ATTORNEY Patented Mar. 7, 1939 PORTABLE PICTURE TRANSDIISSION APPARATUS Harold Carl son, Rutherford, N. J., assignor to The Associated Press, poration of New York New York, N. Y., a cor- Application June 4, 1936, Serial No. 83,441

22 Claims.

This invention relates to a portable picture transmission apparatus.

An object of this invention is to provide a compact picture scanning mechanism of light weight which can be used in' conjunction with present non-portable apparatus in newspaper ofiices.

A further object is to provide a novel method of rotating the picture drum and moving it axially in synchronism with other machines, portable, or non-portable which may be in circuit therewith.

Still another object is the provision of a simple, rugged, and inexpensive mechanism which may be constructed from standard parts with a minimum of special machine work.

In a well-known picture transmission system in use by a number of newspapers, the characteristics of the picture are transmitted over telephone circuits as modulations of a carrier wave at voice frequency. The present invention contemplates the use of a vacuum tube driven fork oscillator of known design operating at a suitable frequency, such as 2400 cycles to drive a synchronous motor for turning the picture drum and vibrating a light valve, also of known construction.

The present invention provides a picture scanning mechanism which can be constructed from standard parts to scan a picture as closely or as coarsely as desired.

In the embodiment shown, only one axial feed rate is contemplated, that is, 200 turns per inch, but it will be readily seen that with a few minor changes that the machine may be adapted to scan more closely or less closely than this rate.

The invention will now be described with the aid of the accompanying drawings of which there are four sheets.

Figure 1 is a front elevation of a picture transmitter constructed according to the present invention.

Figure 2 is a top view.

Figure 3 shows details of the clutch mechanism.

Figure 4 is a vertical section taken through 4-4 of Figure 2.

Figure 5 is an end view of the drum showing details of a lead nut.

Figure 6 is a top View of the clutch mechanism.

Figure '7 is a vertical section'taken through 'I'! of Figure 1.

Figure 8 shows the clutch engaging lever.

Figure 9 is a schematic diagram of a circuit arrangement suitable for use with the present invention.

Referring now to the drawings:

Secured to base I are upright members 2, 3, and 4, which serve to support the various parts of the machine.

The main shaft, a single unit, consisting of a round section 5 and a square section 6 extends through upright member 3 and issupported by suitable bearings in members 2 and 4.

A friction device "I is secured toone end of the main shaft for the purpose of preventing back lash in the various parts of the mechanism. The friction device shown is a modification of the well-known friction clutch used on start stop printing telegraph distributors.

The arrangement shown consists of two driven sections 8 and 9 and a stationary section having an arm [0 which tends to turn with the shaft but is prevented from doing so by pin I I in upright 4. The stationary and moving sections are separated by suitable friction washers I2 and I3. .The particular assembly can be taken down by removing thumb screw I4.

The main shaft is driven by synchronous motor 2|, (Figure 2) which is secured to the members 3 and 4 in such a manner that it can be readily detached for greater portability.

The motor is provided with three legs which are secured respectively in U-shaped openings in brackets 22 by screws 23, two of which are shown. The brackets are in turn attached to upright members 3 and 4 by screws 24 shown in section in Figure 1.

The motor 2| is driven in the present embodiment by 2400 cycle alternating current. In order to start the motor it is necessary that it be brought up to speed or slightly beyond its normal synchronous speed by some external means. The present invention provides for starting the motor as followsi To the shaft 25 of motor 2| is secured a small wheel 26 having a periphery of rubber, leather, or other suitable material.

A lever 2! pivoted on screw 28 and supported by a stud 29 attached to the motor shell carries at one end a wheel 30 which is free to turn on bearing screw 3I. Wheel 30 is of considerably greater diameter than wheel 26 which it overlies. but normally does not engage, due to spring 32 supported between post 33 in the motor shell and post 34 in the lever which holds the wheels out of engagement with each other. The periphery of wheel 30 may, if desired, be of a friction material.

When starting motor 2|, wheels 26 and 30 are brought into engagement by rotating lever 21 motor.

The motor shaft 25 projects beyond disc 36 which is secured thereto. Disc 3! is secured to shaft 38 which also carries worm 39 fast there on. Motor shaft 25 extends into sleeve 40 which is integral with 31 and 38 suificiently to support this assembly, but is not otherwise secured thereto except by springs 8! which form a. yielding connection between the motor and the worm.

Worm 39 drives worm wheel 62 fast on the round section 5 of the main shaft. Secured to the main shaft adjacent to wheel 62 is a gear 50 which meshes with gear 5! on stub shaft 52, supported by upright member 3.

Gear El isfree to turn on shaft 52 and is fast to disc 53 which is part of the driving side of a clutch mechanism which may, at will, form a fixed connection between gear 5! and gear 5 3 also supported by shaft 52.

Gear 5 3 is meshed with gear 55 fast to sleeve 56, in which shaft 5 is free to turn. The sleeve is further supported externally by bearing 5? in upright member 3.

Secured-to sleeve 58 is a threaded sleeve or hollow lead screw 58 which turns with sleeve 56 on the round section 5 of the main shaft between upright 3 and a shoulder formed at the junction of the square section it and the round section 5 of the main shaft.

Drum 58 which is rotated and moved axially on the main shaft is provided with a plate 8d at one end, which carries a lead nut split in two sections, $11 and 62, Figure 5. The part 82 is attached to plate til by shoulder screws 63 which extend through slightly elongated holes in $2.

One end of compression spring 6 extends into an opening in 53 and the opposite end into a similar opening in a block secured to plate (iii, causing the lead nut to engage the hollow screw 58 at all times, thus eliminating back lash and lost motion between these parts.

The opposite end of the drum is supported by plate 66 having an opening which fits closely the square section 6 of the main shaft, yet permits the drum to move axially thereon with a minimum of friction.

The clutch between gears 5i and 5 3 referred to above consists of a driving section supported by plate 53 secured to gear 56, and a driven section consisting of a toothed wheel 84 secured to gear 5 1.

Mounted on plate 53 is a pawl 8'? which pivots on screw 68. The pawl is provided with two notches, 89 and 78, which cooperate with spring pressed detent H pivoted on screw '52 in plate 53.

The detent serves to hold the pawl in either of two positions depending on whether the clutch sections are connected or disconnected.

Pawl 67 has an arm 13 which extends almost to the edge of disc 53. A lever having ofiset arms Hi and 75, Figure 8, is pivoted to plate 53 by screw 78. Arm 75 may move between stop pins 77 and 78, but is normally held against pin H by spring 79.

Pawl 61 is provided with teeth 80 which when detent H rests in notch 69 mesh with similar teeth in wheel 8| (Figure 4) which is rigidly secured to gear 54.

When the detent rests in notch .10, gears 5| and 54 are-disconnected.

The following arrangement is provided for operating the clutch while the machine is in motion.

A bifurcated lever 86 having a handle 81 is pivoted on stud 88 to the frame of the machine. The lever is positioned by a centering device consisting of a second lever 89 also pivoted on stud 88. Springs 90 secured to pins 8i which overlie the arms of lever 88 serve to hold the assembly in a center position.

Lever 86 may be rotated onits pivot in either direction, the limit being determined by stop pins 92 and 93. V

When handle 87 is raised, the end of arm 95 of lever 86 is in the-plane of rotation of the ofiset arm 75 of the clutch operating lever and during the course of clockwise rotation of disc 53, as shown in Figure 3, 15 will engage 943 causing the rotation of :75 on its pivot as indicated by the dotted lines in the drawings, and under these conditions if the clutch has been previously disengaged, the arm l lof the lever will engage arm l3 of the pawl overthrowing the detent and causing the teeth 88 of the pawl to mesh with the teeth on wheel 8i, thus throwing in the clutch.

If handle 87 were similarly rotated, and the clutch were already in, nothing would happen except that arm 715 would be tripped at each revolution of the mechanism. r

The clutch is thrown out or disconnected as follows: When handle 8? is depressed so that lever 86 rests against stop 32, then the offset arm. 95, Figure 6, is in the path of rotation of arm 713, so when the clutch is in, during the course of rotation, with handle 8'11 depressed, arm Q5 will engage arm 73 of pawl Bl rotating pawl 6?, and overthrowing it sufficiently for detent ill to drop into notch 78, positioning the pawl so that arm l3 will clear 95 if 817 is kept depressed during subsequent turns of the machine.

Referring now to Figures 1 and 7: A lever 96 is supported by pivot 97 secured to the frame of the machine. Spring 88 tends to hold arm tilt shaped like a brake shoe out of contact with the hub of gear 55 which it overlies. A stud $9 is provided as a stop for 98.

The shoe tilt may be manually pressed against the hub of gear 55 to stop the wheel when the clutch is out in order to restore the drum to an initial or starting position. This operation will be described in detail below.

Operation Let it be assumed that it is desired to cause the drum to move axially 1/200 of an inch per revolution.

By referring to the drawings it will be seen that a positive direct drive is provided for rotating the drum through worm 39 and worm wheel t2, the latter being secured to the main shaft which has a square section 8 extending through a square opening in the drum end plate 66.

It will be understood, also, that with the clutch out, or disconnected, that the drum will revolve in whatever position it happens to be, without feeding axially.

For the purpose of illustration we will assume that sleeve or hollow lead screw 58 is provided with 20 threads per inch, this being a standard thread of large size and easily cut.

With the present arrangement, if the 75 were turned and the sleeve prevented from turning, then the drum would move axially 1/20 of an inch with each revolution of the drum. Likewise, if the threaded sleeve 58 were rotating at a speed difierent from that of the main shaft, the drum would move axially in either direction, the direction and rate of axial movement being proportional to the difference in speed and direction of the relative movement of the main shaft and the threaded sleeve.

In the present embodiment gears 50 and 5| have a like number of teeth, gears with 34 teeth having been selected.

Gear 54, however has 33 teeth, and gear 55 has '30 teeth.

With each revolution of the main shaft, and with the clutch in, gears 50, 5| .and 54 make one revolution.

If gears 54 and 55 had a like number of teeth, gear 55 and sleeve 58 would also turn with the main shaft and the drum would revolve but not move axially. But this is not the case, since gear 54 is provided with 33 teeth and gear 55 has 30 teeth, sowhen 54 makes a complete revolution, gear 55 is turned 3 teeth or 36 degrees further, which is 1/10 of a turn, so therefore the drum will move axially 1/10 of 1/20 of an inch or 1/200 of an inch.

Obviously, with the arrangement just described, if the difference in speed between the lead screw and the main shaft were 1/20 of a revolution, an axial feed of 1/400 of an inch would be made at each revolution of the drum. Similarly, if the difference were 1/5 of a revolution, the axial feed would be 1/100 of an inch.

After a picture has been scanned, it is necessary to return the drum to a starting point. This is readily accomplished with the present mechanism without stopping the device by rotating lever 96 on its pivot so that shoe I00 rides against the hub of gear 55 holding the gear against rotation. This operation is performed with the clutch out. Under these conditions the drum is quickly returned to its initial position by the relatively coarse thread on the lead screw at the rate of 1/20 of an inch for each revolution of the drum.

The device described above may be used with a known electro-optical system shown in Figure 9, in which the light from a source of illumination IOI is focused by lens I02 on the shutter of light valve I03 which vibrates under the influence of an alternating current from the vacuum tube .driven fork oscillator I04, the alternating current being amplified by amplifier I05.

The pulsating light beam is focused by optical system I06 on'mirror I01 which-reflects arpoint of intense light on a picture secured to drum 59.

Light varying in intensity with the shade of the elemental areas of the picture is reflected from the drum and focused by mirrors I08 and I09 on a photo electric cell IIO, causing a pulsating current of varying amplitude to pass through amplifier III, band pass filter H2, and attenuator H3, or any suitable network to line II4.

Vacuum tube driven fork oscillator I04 also produces an alternating current for driving moinvention has been herein shown and described, it will be understood that numerous details of the arrangement may be altered without departing from the spirit of this invention as defined by the following claims.

What is claimed is:

1. In a device of the character described, a picture drum, means for supporting said drum, threaded nut means secured to said drum, differential driving means effective solely through the instrumentality of said supporting means for causing the rotation of said drum and for imparting an axial feed thereto of a pitch differing from that of the threaded nut.

2. In a .device of the character described, a picture drum, a rotary shaft for supporting said drum, a threaded nut secured to said drum through which said shaft extends, and differential driving means effective solely through the instrumentality of said shaft for imparting an axial feed to said drum at a rate differing from the pitch of said threaded nut.

3. In a device of the character described, a picture drum, a rotary shaft for supporting said drum having a rounded section and a nonrounded section, threaded means concentrically d1sposed on said rounded section of said shaft, a threaded nut secured to said drum arranged to turn on said threaded section, and means effective solely through the instrumentality of said shaft for imparting a rotary movement and also an axial movement of a different pitch from that of the threaded section.

4. In a device of the character described, a picture drum, a shaft forming an axis for said drum, means for rotating said drum, means for moving the drum axially and means for stopping or reversing the axial movement of the drum without interrupting its rotary movement.

5. In a device of the character described, a picture drum, a shaft forming an axis for said drum, and means effective solely through said shaft for rotating the drum and moving the drum axially, and means for stopping or reversing the axial movement of the drum without interrupting its rotary motion.

6. In a device of the character described, a picture drum, a. shaft forming an axis for said drum and means effective solely through said shaft for rotating the drum and for moving the drum axially at a rate suitable for scanning, and also for moving the drum axially at a rate greater than that for scanning.

'7. In a device of the character described, a picture drum, a shaft forming an axis for said drum, means effective solely through said shaft for rotating the drum and moving the drum axially at a rate suitable forscanning and for moving the drum axially at a rate greater than .that for scanning without interrupting the rotary 9. In a device of the character described, a

picture drum, a support therefor comprising a shaft having a round section and a non-circular ,section, a threaded sleeve over said round section, a pair of end plates for said drum, one plate being provided with an aperture fitting the noncircular section of said shaft and the other being provided with threads to fit said threaded sleeve,

and means to cause said drum to rotate and feed axially at a pitch differing from that of the threaded sleeve.

10. In a device of the character described, a picture drum, a support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, a pair of end plates for said drum, one plate being provided with an aperture fitting the non-circular section of said shaft and the other being provided with threads to fit said threaded sleeve, and. means for driving said shaft and said threaded sleeve at different rates from a common source of power.

11. In a device of the character described, a

v picture drum, a support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, a pair of end plates for said drum, one plate being provided with an aperture fitting the noncircular section of said shaft and the other being provided with threads to fit said threaded sleeve, independent means for drivingsaid shaft and said sleeve from a common source of power, and a clutch between one of said means and said source of power.

12. In a device of the character described, a picture drum, a support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, a pair of end plates for said drum, one plate being provided with an aperture fitting the non-circular section of said shaft and the other being provided with threads to fit said threaded sleeve, independent means for driving said shaft and said sleeve from a common source of power, and a clutch between said sleeve and said source of power.

13. In a device of the character described, a picture drum, a support therefore comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section and driving means for producing a differential movement between said sleeve and said shaft and thereby producing an axial movement of said drum.

14. In a device of the character described, a picture drum, a support therefor comprising a shaft having a' round section and a non-circular section, a threaded sleeve over said round section and driving means for producing a differential movement between said sleeve and said shaft in order to producean axial movement of said drum at a rate suitable for scanning, and means for restraining the rotation of said threaded sleeve to cause the drum to move axially at a rate greater than that for scanning.

15. In a device of the character described, a picture drum, a support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, means for rotating said sleeve and said shaft from a common source of power at different rates; clutch means and brake means cooperating with the sleeve drive mechanism whereby the drum may be moved axially on said shaft in opposite directions at different rates.

16. In a device of the character described, a picture drum, a support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, a pair of end plates for said drum, one plate I being provided with an aperture fitting the nonanger-r circular section of said shaft and the other being provided with threads to fit said threaded sleeve, a motor for driving said shaft, a gear on said shaft meshing with a first gear of a pair of idler gears, a gearsecured to said sleeve meshing with the second gear of said pair, and means to operatively connect or disconnect the gears of said pair.

1'7. In a device of thecharacter described, a picture drum, a support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, a pair of end plates for said drum, one plate being provided with an aperture fitting the noncircular section of said shaft and the other being provided with threads to fit said threaded sleeve, a motor for driving said shaft, a gear on said shaft meshing with a first gear of a pair of idler gears, a gear secured to said sleeve meshing with the second gear of said pair, and means settable to become effective at a predetermined point in a cycle of operation to connect operatively one idler gear with the other.

18. In a device of the character described, a picture drum, a support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, a pair of end plates for said drum, one plate being provided with an aperture fitting the noncircular section of said shaft and the other being provided with threads to fit said threaded sleeve,

a motor for driving said shaft, a gear on said shaft meshing with a first gear of a pair of idler gears, a gear secured, to said sleeve meshing with the second gear of said pair, and means settable to become effective at a predetermined point in a cycle of operation to disconnect one idler gear from the other.

19. In a device of the character described, a picture drum, a support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, a pair of end plates for said drum, one plate being provided with an aperture fitting the non-circular section'of said shaft and the other being provided with threads to fit said threaded sleeve, a motor for driving said shaft, a gear on said shaft meshing with a first gear of a pair of idler gears, a gear secured to said sleeve meshing with the second gear of said pair, a ratchet wheel disposed between said idler gears and secured to one of said pair, a pawl and supporting means therefor secured to the other gear of said pair, and a detent carried by said pawl supporting means for retaining said pawl in an engaged or disengaged position with said ratchet.

20. In a device of the character described, a picture drum, a support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, a pair of end plates for said drum, one plate being provided with an aperture fitting the non-circular section of said shaft and the other being provided with threads to fit said threaded sleeve, a motor for driving said shaft, a gear on said shaft meshing with a first gear of a pair of idler gears, a gear secured to said sleeve meshing with the second gear of said pair, a ratchet wheel disposed between said idler gears and secured to one of said pair, a pawl and supporting means therefor secured to the other gear of said pair, a detent carried by said pawl supporting means for retaining said pawl in an engaged or disengaged position with said ratchet, and a lever for operating said pawl.

21. In 'a device of the character described, a picture drum, a support therefor comprising a shaft having a roundsection and a non-circular section, a threaded sleeve over said round section, means for rotating said sleeve and said shaft from a common source of power at different rates; clutch means-and brake means cooperating with the sleeve drive mechanism whereby the drum may be moved axially on said shaft in opposite directions at different rates, and means for correcting back lash in the respective parts comprising a friction clutch.

22. In a device of the character described, a picture drum, 9. support therefor comprising a shaft having a round section and a non-circular section, a threaded sleeve over said round section, means for rotating said sleeve and said shaft from a common source of power at different rates; clutch means and brake means cooperating with the sleeve drive mechanism whereby the drum may be moved axially on said-shaft in opposite directions at different rates, and means for correcting back lash in the respective parts comprising a friction clutch having a rotary element secured to said shaft, and a nonrotary element retained by a supporting member for said shaft.

HAROLD CARLSON. 

